To determine whether the door and window bearings need to be replaced, the following key phenomena can be comprehensively judged to promptly identify problems and avoid affecting use:

1、 Abnormal operating status

Smooth rotation: When manually rotating the bearing, if there is jamming, sticking, or obvious resistance, or if there is a sharp friction sound such as "creaking" or "creaking" during rotation (normally a uniform and low "buzzing" sound), it indicates that there may be wear or foreign objects stuck inside the bearing.

Excessive clearance: Gently shake the outer and inner rings of the bearing. If the clearance between the two is significant (such as exceeding the original standard value by 1.5 times), or if the shaking increases when moving doors and windows by hand, it indicates that the bearing is severely worn and needs to be replaced.

2、 Appearance damage and aging

Component cracking or fracture: Check for cracks, gaps, or fragments in the inner and outer rings, rolling elements, and cage of the bearing. If such conditions exist, the bearing cannot be used safely.

Surface damage: If there are obvious scratches, indentations, rust or discoloration due to overheating (such as blackening or yellowing) on the raceway surface and rolling elements, or if the retainer is severely worn or the rivets are loose, they all need to be replaced.

Seal failure: If the bearing seal ring/dust cover is damaged or deformed, causing grease leakage or dust to enter, it will accelerate internal wear and require timely replacement of the seal or the entire bearing.

3、 Functional impact and safety hazards

If the bearing problem causes the doors and windows to lag or tilt, or accompanied by abnormal noise and increased vibration, it not only affects the user experience, but may also pose safety risks due to structural instability. It is recommended to immediately replace the bearing with the appropriate model to ensure stable operation of the doors and windows.

If any of the above situations occur, it is recommended to prioritize selecting products that match the original bearing specifications (such as material, size, load-bearing parameters), and pay attention to cleanliness and concentricity during installation to avoid further damage due to improper fitting.